1213221120 has 144 divisors (see below), whose sum is σ = 3979913280. Its totient is φ = 314744832.

The previous prime is 1213221077. The next prime is 1213221137. The reversal of 1213221120 is 211223121.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 1213221120.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 137811 + ... + 146349.

Almost surely, 2^1213221120 is an apocalyptic number.

1213221120 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1213221120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1989956640).

1213221120 is an abundant number, since it is smaller than the sum of its proper divisors (2766692160).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1213221120 is an equidigital number, since it uses as much as digits as its factorization.

1213221120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8600 (or 8586 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

The square root of 1213221120 is about 34831.3238335840. The cubic root of 1213221120 is about 1066.5469726804.

Adding to 1213221120 its reverse (211223121), we get a palindrome (1424444241).

The spelling of 1213221120 in words is "one billion, two hundred thirteen million, two hundred twenty-one thousand, one hundred twenty".